interesting pair of signals (indicated by 'a' and 'b'), FMCW and 500 kHz spaced, most likely from the same OTH Radar (RAF Cyprus ?). Both occupy 20 kHz of bandwidth with 25 sps sweep-rate.
The left signal (a) is 'down-chirped' (sweeps start from the higher frequency and terminate at the lower frequency, ie descending freq.) while the right one (b) is 'up-chirped' (ascending freq.)
The left signal (a) is 'down-chirped' (sweeps start from the higher frequency and terminate at the lower frequency, ie descending freq.) while the right one (b) is 'up-chirped' (ascending freq.)
Note the two sounders of this radar: they start and stop at frequencies which are equidistant from the two signals (in a neighborhood of the two signals) and have the same chirp pattern (down and up) of the two radar signals to which they are subservient.
It could be assumed the that the frequency management of the doubled radar signal is achieved just by using these sounder.
I receive something similar on 144008.554 Mhz over the Black Sea. The signal is in horizontal polarization and is very frequency stable.
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